Carnot engine

quick question, is the difference between a carnot engine to an engine is that the engines eff is less than or equal 1-(cold temp / hot temp), and the carnot is the max of this which is just equal 1-(cold temp / hot temp)?

quick question, is the difference between a carnot engine to an engine is that the engines eff is less than or equal 1-(cold temp / hot temp), and the carnot is the max of this which is just equal 1-(cold temp / hot temp)?

That's about it. This idea is the basis of Carnot's theorem.

A Carnot engine is essentially a reversible heat engine and since there are no truly reversible heat engines, it therefore follows that a Carnot engine represents the maximum efficiency achievable.